Proton GE, the unofficial build of Proton mainly for use with Steam Play (but you can use it outside Steam too - like with Lutris) has a big new release out with Proton 5.0 GE 1.
Why would you use Proton GE instead of the official version included with Steam? Valve/CodeWeavers sometimes take a while to update it and certain games made need fixes sooner that Proton GE provides.
So what's new? Well, a lot! Multiple parts got updated to the latest versions including Wine, DXVK 1.5.3, FAudio and Vkd3d bringing compatibility with Windows-only titles even futher forward. There's also plenty of fixes added for games like Far Cry 5, Monster Hunter World, Black Ops 2, Endless Legend, For Honor, the Battle.net Beta should no longer crash if your Winecfg is set to Windows 10 be sure to see the release notes here.
Installing it is easy enough too. Simply download the tar.gz package from the release notes (at the bottom), extract it and place the Proton GE folder into:
Note: The tilde is a shortcut for your Home folder, the dot before "steam" means it's a hidden folder.
Once done, reload Steam and it will be available as a version for you to force on a game when you right click and go into the Properties:
Want to get a DOSBox game running nicely on Linux through Steam, one that doesn't have a Linux build? You can also try Boxtron which had an update earlier this month.